infection at a dog breeding facility in the Madrid region: Infection rate and clinical management based on toltrazuril metaphylaxis

Canine coccidiosis caused by Cystoisospora canis and Cystoisospora ohioensis-complex is common in kennels. While often underestimated, coccidiosis may cause severe clinical signs in puppies and sometimes even lead to death, so preventative measures are important. This study examines Cystoisospora spp. infection at a Labrador retriever breeding facility in Madrid, Spain. To identify environmental factors associated with infection, dams were examined throughout a reproductive cycle (from oestrus to 60 days postpartum) and their puppies during their first 60 days of life. Also assessed was the efficacy of combined treatment with emodepside (0.9 mg/ml) and toltrazuril (18 mg/ml) at a dose of 0.5 ml/kg of weight, equivalent to 0.45 mg/kg and 9 mg/kg, respectively, in puppies on day 35 of life. Oocyst shedding was detected in 4.6-18.6% of 45 dams examined and in 2.2-9.1% of their litters (315 puppies). In both cases, peak opg elimination was recorded on day 30 postpartum/of life. The species of Cystoisospora detected were C. canis (91.3%) and C. ohioensis-complex (8.7%). While in both dams and puppies opg counts were higher in autumn when rainfall was at its highest, correlation between opg and rainfall emerged as significant only in puppies (p = 0.031). The treatment of 35 day-old puppies with toltrazuril was 100% effective in controlling this infection in the kennel. Our findings therefore suggest the need for a strict hygiene regime and the use of toltrazuril as blanket treatment to reduce Cystoisospora transmission in dog breeding facilities.

Parasitological and molecular investigation of consequences of raw meat feeding (BARF) in dogs and cats: implications for other pets living nearby

Considering the original nature of carnivorism among dogs and cats, nowadays these pets are increasingly fed BARF (Biologically Appropriate Raw Food/Bone And Raw Food) diet to improve their health conditions. However, this diet may also carry health risks, such as vitamin or mineral deficiencies, and infection with pathogens including parasites. In our study, fecal samples of 89 pet animals kept on BARF diet were subjected to coprological examination followed by molecular analyses. Six of them shed eggs of Dicrocoelium dendriticum. This result was confirmed with PCR and sequencing, and in one case, the DNA of Fasciola hepatica was also demonstrated. In addition, oocysts of Cystoisospora canis, a Cystoisospora ohioensis-like sp. and Eimeria stiedai, as well as sporocysts of a Sarcocystis sp. were also detected. All samples were negative for Neospora caninum and Toxoplasma gondii. In conclusion, no evidence was found for the infection of BARF-fed dogs and cats with parasites that are usually associated with this diet and considered as clinico-pathological risk factors for these pets themselves (e.g., N. caninum, T. gondii). However, fluke eggs (probably originating from ruminants) and oocysts of E. stiedai (from rabbit liver in the food) were demonstrated as pseudoparasites. These species are usually not considered among parasite-associated risks of BARF-feeding, implying that other animals living near BARF-fed pets are neglected in this context. However, where intermediate hosts of D. dendriticum occur in urban areas, BARF-feeding may indirectly affect later other dogs and cats. It was also shown here that BARF-feeding may contribute to the contamination of the environment with E. stiedai oocysts, thus increasing the risks of biliary coccidiosis in nearby living pet rabbits that would otherwise not have access to oocysts of E. stiedai.

On the efficacy of preventive toltrazuril treatments and the diagnosis of Cystoisospora suis infections in intensively raised piglets in farms from southeast Spain

This study investigated the presence and abundance of Cystoisospora suis oocysts in faecal samples from 131 one- to three-week-old pig litters belonging to eight intensively raised, indoor herds in Spain. Seven herds used preventive anticoccidial toltrazuril treatments administered orally or by intramuscular injection, and one did not use preventive anticoccidial treatments. The diagnosis was performed using two oocyst flotation-concentration methods, Bailenger's method in every herd and the more recent Joachim's method in four herds. Oocysts were detected in every farm, the proportion of oocyst-positive samples was higher with Bailenger's technique, and the estimated overall prevalence (95% confidence interval) was 40 (32-49)%, including 47 (29-65)% in non-medicated litters, 52 (38-67)% in orally medicated litters and 28 (16-40)% in intramuscularly medicated litters (p < 0.05). However, mixed logistic regression models indicated that the risk of infection was not significantly associated with preventive anticoccidial treatments (p > 0.05), and increased with age, was higher in herds with partially compared to fully slatted dung floors in farrowing pens and in litters with pigs with diarrhoea (p < 0.05). The median (range) oocysts per gram of faeces (OpG) in infected litters by Bailenger's method was 623 (35-49048) and mixed negative binomial models revealed no significant association between infection intensity in positive litters and pen's floor type and piglets age, faecal consistency and treatment status (p > 0.05). The apparent low efficacy of Toltrazuril suggests treatment administration failures, reduced residual efficacy or low susceptibility of C. suis strains in study farms and needs further investigation.

(Apicomplexa: Eimeriidae) from the warbling vireo Vireo gilvus Vieillot (Passeriformes: Vireonidae) in Morelia, Mexico

A new coccidian species, Isospora gilvusi n. sp. (Apicomplexa: Eimeriidae) collected from the warbling vireo Vireo gilvus, is reported from Morelia, Michoacán State, Mexico. Sporulated oöcysts of the new species are spherical to subspherical, 27-31 × 27-29 (30.1 × 28.4) μm, with a length/width (L/W) ratio of 1.1; one or two polar granules are present, but micropyle and oöcyst residuum are absent. Sporocyts are ovoid to drop-shaped, 16-17 × 11-12 (17.0 × 11.5) μm, with a L/W ratio of 1.7; Stieda and sub-Stieda bodies are both present, but para-Stieda body is absent; sporocyst residuum diffuse. At the histological study, endogenous stages were observed in the epithelial cells of the duodenum. This is the second species of Isospora recorded infecting a bird of the family Vireonidae in the New World.

(Apicomplexa: Eimeriidae) from the black-polled yellowthroat Geothlypis speciosa Sclater, 1859 (Passeriformes: Parulidae) in Ciénegas del Lerma, Mexico

A new coccidian species, Isospora speciosae n. sp. (Apicomplexa: Eimeriidae) collected from the black-polled yellowthroat Geothlypis speciosa Sclater, is reported from the marsh Ciénegas del Lerma Natural Protected Area, Mexico. Sporulated oöcysts of the new species are subespherical to ovoidal, 24-26 × 21-23 (25.7 × 22.2) μm, with a length/width (L/W) ratio of 1.1; one or two polar granules are present, but micropyle and oöcyst residuum are absent. Sporocyts are ovoidal, 17-19 × 9-11 (18.7 × 10.2) μm, with a L/W ratio of 1.8; Stieda and sub-Stieda bodies are both present, but para-Stieda body is absent; sporocyst residuum compact. The new species is the sixth species of Isospora recorded in a bird of the family Parulidae in the New World.

THE PHARMACOKINETICS AND PHARMACODYNAMICS OF ORAL PONAZURIL IN THE TREATMENT OF SYSTEMIC ISOSPOROSIS IN PASSERINE BIRDS

Systemic isosporosis, previously atoxoplasmosis, is a significant cause of mortality in juvenile passerine birds. Recommended treatment regimens are empiric and vary in efficacy. The goal of this study was to determine the pharmacokinetics and pharmacodynamics of ponazuril for treatment of systemic isosporosis. Ponazuril, diluted with water to create an oral suspension (50 mg/ml), was administered (100 mg/kg) to 72 European starlings (Sturnus vulgaris) by a single dose via direct oral gavage (n = 24), a single dose injected into superworm larvae (Zophobas morio; n = 24), or a daily dose mixed with commercial dog food to top-dress feed for 5 d (n = 24). Peak plasma concentrations were 5.84, 2.46, and 9.13 µg/ml for the direct gavage, injected larvae, and top-dressed feed groups, respectively. With repeated dosing, mean plasma concentrations from the top-dressed feed group were maintained between 8.12 to 13.11 µg/ml. Results suggested ponazuril at a dosage of 100 mg/kg administered via direct gavage or top-dressed feed, but not via injected larvae, would exceed the concentrations needed to inhibit merogony of other apicomplexan parasites in cell culture (5 µg/ml). To assess the pharmacodynamics of this dose, seven passerine birds, red-vented bulbuls (Pycnonotus cafer; n = 2), blue-grey tanager (Thraupis episcopus; n = 1), and red-capped cardinals (Paroaria gularis; n = 4), were identified as shedders of systemic Isospora spp. via fecal qPCR. Birds were then treated with ponazuril (100 mg/kg) daily on top-dressed feed for 14 d. Fecal shedding was assessed via qPCR for 6 wk from the initiation of treatment. Treatment was associated with reduction in proportions of fecal shedding during the treatment period and the week following treatment, but shedding resumed in all birds by the end of sampling. Results support that treatment of breeding birds with 100 mg/kg ponazuril could reduce the shedding of active oocysts and decrease risk of clinical infection in susceptible juveniles.

Cystoisospora suis infection in suckling piglets in Brazil: Prevalence and associated factors

Piglet coccidiosis is a parasitic disease caused by the protozoan Cystoisospora suis, which is regarded as the most prevalent gastrointestinal parasite in intensive pig farms. Despite the availability of highly effective chemo-metaphylaxis (toltrazuril), coccidiosis is still prevalent in European and other countries. We conducted a cross-sectional study on swine farms in Brazil, to assess the prevalence of Cystoisospora suis in fecal samples and determined the associated factors. In total, 666 litters from 50 farms were sampled twice within one week between samplings (mean age at sampling: 10.75 and 17.7 days). Of 666 litters, 225 (33.8%) were positive at least once, and the expected within farm prevalence of C. suis oocysts was 32.9% (25.4-41.3%; 95% confidence interval). Oocysts were more prevalent in fecal samples collected from farms with diarrhea (odds ratio = 6.75). The room temperature was also positively associated with oocyst detection; a one-degree increase in room temperature increased the chance of a litter being positive by 23.2%. Up-to-date, this is the most comprehensive technical evidence of factors associated with C. suis infection in Brazilian industrial piglet farms.

A New Isospora (Apicomplexa: Eimeriidae) from the Carolina Wren, Thryothorus ludovicianus ludovicianus (Passeriformes: Certhioidea: Troglodytidae), in Southeastern Oklahoma, USA

PURPOSE

Nothing is known of the coccidian parasites of the Carolina wren, Thryothorus ludovicianus ludovicianus (Latham, 1790). Here, we report a new species of Isospora from T. l. ludovicianus from Oklahoma, USA.

METHODS

Faecal samples were collected between September and December 2021 from five adult T. l. ludovicianus taken with a mist net from McCurtain County, Oklahoma, USA, and examined for coccidian parasites. Samples were placed in individual vials containing aqueous potassium dichromate. They were examined for coccidia after flotation in Sheather's sugar solution, measured, and photographed. Tissue samples from the intestine of a single positive bird were removed and placed in 10% neutral-buffered formalin for examination of coccidian endogenous stages.

RESULTS

A single Carolina wren (20%) was found to be passing a new species of Isospora. Oocysts of Isospora edwardwilsoni n. sp. were subspheroidal to ovoidal with a smooth bi-layered wall, measured (L × W) 23.8 × 20.3 µm, and had a length/width (L/W) ratio of 1.2; a micropyle and oocyst residuum was absent but typically one to up to four polar granule(s) was present. Sporocysts are ovoidal to ellipsoidal and measured 15.3 × 9.7 µm, L/W 1.6; a knob-like Stieda body was present as well as a distinct rounded sub-Stieda body. The sporocyst residuum was composed of various-sized granules in a compact irregular mass or dispersed between and across the sporozoite, or a combination of both within the same sporocyst. Information is also presented on the endogenous development of this coccidian.

CONCLUSION

This is the first coccidian reported from T. l. ludovicianus and, more importantly, the first known from the members of the family Troglodytidae in North America.

Failure to eradicate Isospora belli diarrhoea despite immune reconstitution in adults with HIV--a case series

Isospora belli causes diarrhoea in patients with AIDS. Most respond to targeted therapy and recommendations are that secondary prophylaxis can be stopped following immune reconstitution with ART. We report eight cases of chronic isosporiasis that persisted despite standard antimicrobial therapy, secondary prophylaxis, and good immunological and virological response to ART. Median CD4 nadir was 175.5 cells/mm(3) and median highest CD4 while symptomatic was 373 cells/mm(3). Overall 34% of stool samples and 63% of duodenal biopsy specimens were positive for oocytes. Four patients died, two remain symptomatic and two recovered. Possible explanations for persistence of symptoms include host factors such as antigen specific immune deficiency or generalised reduction in gut immunity. Parasite factors may include accumulating resistance to co-trimoxazole. Research is required to determine the optimum dose and duration of co-trimoxazole therapy and whether dual therapy may be necessary. Mortality was high and pending more data we recommend extended treatment with high-dose co-trimoxazole in similar cases.

Isospora belli superinfection in a patient with eosinophilic gastroenteritis--a diagnostic challenge

Isospora belli infection, characterized by peripheral blood eosinophilia, is often seen as an opportunistic infection in patients with acquired immunodeficiency syndrome (AIDS). It is also reported in patients with underlying lymphoproliferative disorders including lymphoma and leukemia. Eosinophil-associated gastrointestinal disorders (EGID), including eosinophilic gastroenteritis (EGE), is characterized by eosinophilic infiltration of the gastrointestinal (GI) tract with various GI symptoms. We report a case of a 50-year-old male who developed Isospora superinfection of the small bowel while receiving systemic corticosteroids for EGE. He presented with worsening diarrhea, abdominal pain, nausea and vomiting with worsening peripheral eosinophilia. I. belli infection was diagnosed by the detection of oocysts in stool samples and by the presence of the parasite on duodenal biopsy in the background of tissue eosinophilia. I. belli can cause severe chronic diarrhea in immunocompromised patients on corticosteroids. Trimethoprim-sulfamethoxazole often provided rapid cure. Even though peripheral blood eosinophilia was seen in both EGE and Isospora infection, the identification of subnuclear protozoal inclusions as a new histologic finding, as well as the absence of this finding in previous duodenal biopsies coupled with the continued presence of tissue eosinophilia, favored a parasitic superinfection in the setting of underlying EGE.

Severe diarrhea due to Isospora belli in a patient with thymoma

Opportunistic isosporidial infection of the gastrointestinal tract is frequently encountered in patients with acquired immunodeficiency syndrome (AIDS) and is considered to be an AIDS-defining illness. Chronic severe watery diarrhea due to Isospora belli has also been reported in other immunodeficiency states. This report describes severe chronic debilitating diarrhea due to isosporiasis in a patient with mediastinal thymoma, a common tumor of the anterior mediastinum, originating from the epithelial cells of the thymus. Numerous oocysts of I. belli were detected in direct smear preparation of the diarrheic stool sample of the patient, who had an 8-month history of recurrent diarrhea. Duodenal and colonic mucosal biopsies revealed slight degrees of atrophic changes associated with infiltration of the lamina propria by an appreciable number of eosinophiles and the presence of unizoit tissue cysts of I. belli in the surface epithelium of the duodenal mucosa. The patient was first treated with trimethoprim-sulfamethoxazole and subsequently underwent complete thymectomy. Later, due to recurrence of the diarrhea, he was treated with ciprofloxacin.

A rare diarrheic parasite in a liver transplant patient: Isospora belli

We describe the first case of isosporiasis in a liver transplant patient. Watery diarrhea due to Isospora belli was observed in a woman who had undergone liver transplantation 8 months prior. She was successfully treated with trimethoprim-sulfamethoxazole. This parasite should be taken into consideration as an opportunistic infection in transplant patients who need increased hygienic awareness.

Canine isosporosis - epidemiology of field and experimental infections

Isospora spp. are the causative agents of canine isosporosis. Of the 3590 diagnostic samples from Austrian dogs (≤2 years old), 8.7% contained Isospora oocysts, 78% of which from dogs up to 4 months of age. Non‐haemorrhagic and haemorrhagic diarrhoea were significantly more prevalent in Isospora‐infected animals than in coccidia‐negative ones. Twelve of 15 litters from a large commercial dog breeding unit (examined from the third to the 10th week of life) also excreted Isospora (average prevalence: 36.4%) in intensities from 333 to 35 000 oocysts per gram of faeces (opg). In experimental trials 26 3‐week‐old Beagle puppies were infected with low (600–6000), medium (10 000) or high (20 000) dose of Isospora ohioensis‐group or Isospora canis field isolates. Additionally 21 puppies were infected as above and treated with a symmetrical triazintrione. Parasitological and clinical parameters were examined. The two Isospora species differed significantly concerning intensity and duration of excretion. The pre‐patent period was 6–7 days for I. ohioensis and 10–12 days for I. canis. The latter species showed significantly longer excretion and higher opg. This was not influenced by simultaneous infections with both species. Individual patterns of faecal consistency were very variable, irrespective of the infection dose. Treatment significantly reduced both the intensity and the duration of oocysts excretion as well as diarrhoea in comparison with the infected, untreated group and thus proved to be effective against coccidiosis in experimental infections.

Endometrial coccidiosis

This report describes a case of granulomatous endometritis caused by coccidiosis in an immunologically uncompromised 63 year old patient. The glandular epithelium of the endometrium contained numerous intracytoplasmic cysts, corresponding to periodic acid Schiff positive and methenamine silver negative sporoblasts. The endometrial glands revealed reactive phenomena, such as eosinophilic and squamous glandular metaplasia and intraluminal desquamation. Non-necrotising epithelioid granulomata, lacking the presence of parasites, were present in the stroma. Although not detected in the stool examination, the organisms were probably Isospora belli. There was no evidence of other foci of the disease. Coccidiosis should be differentiated from the more commonly occurring coccidiomycosis.

Isosporiasis in Venezuelan adults infected with human immunodeficiency virus: clinical characterization

A cross-sectional study was undertaken to determine the prevalence of isosporiasis and its clinical and laboratory pattern in Venezuelan patients infected with human immunodeficiency virus (HIV) (n = 397). At enrollment, they underwent a thorough clinical history and physical examination, and provided stool specimens for the identification of Isospora belli and other parasites. Isospora belli was identified in 56 subjects (14%) and diarrhea, either acute or chronic, was present in 98% of these cases (P < 0.001). Eosinophilia was strongly associated with isosporiasis (P = 0.01). It was also found that the presence of eosinophilia was more common in I. belli-infected patients without weight loss (P < 0.001). Twenty-six (81.25%) subjects with I. belli infection had CD4+ cell counts < 200 cells/mm3 (P = 0.03). In addition, the data and its description shows the association to be < 100 cells/mm3. This infection seems to be seasonal because the recovery of oocysts occurred mainly in months with significant rainfall. In fact, isosporiasis should be suspected in HIV-infected patients from tropical countries with diarrhea, weight loss, eosinophilia, and low CD4+ cell counts.

A randomized, controlled trial

BACKGROUND

In developing countries, Isospora belli and Cyclospora cayetanensis frequently cause chronic diarrhea in HIV-infected patients.

OBJECTIVE

To compare 1 week of trimethoprim-sulfamethoxazole treatment and 1 week of ciprofloxacin treatment in HIV-infected patients with chronic diarrhea caused by I. belli and C. cayetanensis.

DESIGN

Randomized, controlled trial.

SETTING

HIV clinic in Port-au-Prince, Haiti.

PATIENTS

42 HIV-infected patients with chronic diarrhea due to I. belli (n = 22) or C cayetanensis (n = 20).

INTERVENTIONS

Patients were randomly assigned to receive oral trimethoprim-sulfamethoxazole (160 mg or 800 mg) or ciprofloxacin (500 mg) twice daily for 7 days. Patients who responded clinically and microbiologically received prophylaxis for 10 weeks (1 tablet orally, three times per week).

MEASUREMENTS

Treatment success was measured by cessation of diarrhea and negative stool examination at day 7. Prophylaxis success was measured by recurrent disease rate.

RESULTS

Diarrhea ceased in all 19 patients treated with trimethoprim-sulfamethoxazole. Eighteen of 19 patients had negative results on stool examination at day 7 (95%). Among the 23 patients who received ciprofloxacin, diarrhea ceased in 20 (87% [CI; 66% to 97%]) and 16 had negative results on stool examination at day 7 (70%). By survival analysis, diarrhea from isosporiasis and cyclosporiasis ceased more rapidly with trimethoprim-sulfamethoxazole than with ciprofloxacin. All patients receiving secondary prophylaxis with trimethoprim-sulfamethoxazole remained disease-free, and 15 of 16 patients receiving secondary prophylaxis with ciprofloxacin remained disease-free.

CONCLUSIONS

A 1-week course of trimethoprim-sulfamethoxazole is effective in HIV-infected patients with cyclosporiasis or isosporiasis. Although ciprofloxacin is not as effective, it is acceptable for patients who cannot tolerate trimethoprim-sulfamethoxazole.

Enteric parasites and AIDS

OBJECTIVE

To report on the importance of intestinal parasites in patients with AIDS, showing relevant data in the medical literature, with special emphasis on epidemiology, diagnosis and treatment of enteroparasitosis, especially cryptosporidiosis, isosporiasis, microsporidiasis and strongyloidiasis.

DESIGN

Narrative review.

Comparative features of double-contrast barium studies in patients with isosporiasis and strongyloidiasis

OBJECTIVE

To compare the gastrointestinal features of isosporiasis and strongyloidiasis.

METHODS

Two patients with isosporiasis and three patients with strongyloidiasis were assessed by double-contrast radiography of the duodenum and small intestine, with reference to histology of the duodenal biopsy specimens.

RESULTS

Both conditions affected the duodenum and the proximal jejunum, and showed similar radiographic changes as the diseases progressed. Thus, three patients with diarrhoea lasting 1 year or less showed only minimal or irregularly thickened mucosal folds, which seemed to result from mucosal inflammation. Two patients with long-standing disease periods (17 years and 30 years) presented a markedly granular mucosal appearance with effacement of the folds on radiography. These chronological differences in the radiographic features seemed to reflect the degree of villous atrophy.

CONCLUSION

Isosporiasis has similar radiographic features of strongyloidiasis.

[A case of AIDS complicated with isosporiosis as initial manifestation]

We reported a Thailander patient with isosporiasis accompanied by AIDS. The 34-year-old male, who had been living in Japan for six years, was admitted to our hospital complaining of diarrhea and body weight loss. After admission the patient developed acute renal failure due to dehydration resulting from diarrhea. Laboratory findings on admission showed neither significant microorganisms nor parasite ova in the stool. The patients was given both an intestinal drug and an antibacterial agent, but is vain. Frequent stool examinations disclosed Isospora oocyst in the feaces. Co-trimoxazole was administered resulting in remarkable diarrheal improvement. Renal function was also improved without dialysis. Although isosporiasis is rarely found in Japan, it is stressed that in the AIDS patient with persistent diarrhea who may develop a parasitic disease as did in this case, frequent fecal examinations should be conducted.

Enteropathy in Zambians with HIV related diarrhoea: regression modelling of potential determinants of mucosal damage

BACKGROUND

AIDS is characterised by small intestinal mucosal damage, but its aetiopathogenesis is poorly understood. Enteric infections in Africa differ from those in northern countries, where protozoan infections have been associated with severe enteropathy in AIDS patients.

AIMS

To characterise enteropathy in Zambian AIDS patients compared with local controls, and to assess relative contributions of enteric infection, nutritional impairment, and immune dysfunction.

METHODS

Computer aided mucosal morphometry of small intestinal biopsy specimens from 56 HIV infected Zambians with persistent diarrhoea and 26 diarrhoea free controls, followed by regression modelling.

RESULTS

Patients with HIV related diarrhoea had reduced villous height and increased crypt depth compared with controls. There was no difference between HIV positive and negative controls. In regression models applied to AIDS mucosal measurements, villous height and crypt depth were related to nutritional parameters and to serum soluble tumour necrosis factor receptor p55 concentration. Crypt depth was also related to lamina propria plasma cell count. Intestinal infection was found in 79%, which consisted predominantly of microsporidia in 34%, Isospora belli in 24%, and Cryptosporidium parvum in 21%, but detection of these enteropathogens was not related to severity of enteropathy.

CONCLUSIONS

Nutritional and immune disturbances were associated with enteropathy, accounting for over one third of the variation in mucosal morphometric parameters.

[A clinical and biological study of parasitic and fungal diarrhea in immunosuppressed patients in an urban and suburban area of Yaoundé]

We studied 66 cases of intestinal mycosis and parasitosis in patients infected with the human immunodeficiency virus with chronic diarrhea. All subjects were from the Yaounde urban area and were followed between February and December 1996. They were recruited from 3 hospitals in the center of Yaounde and were aged between 2 and 52 years. There was weight loss in 80.3% and severe dehydration in 72.3% of cases. Feces consisted mostly of watery stools similar to those of cholera patients (50% of cases) and loose stools (43.9% of cases). Parasitic agents were detected in 31.8% and fungal agents in 80.5% of cases. The opportunistic Protozoans detected included Cryptosporidium parvum (15.8%), microsporidia (8.8%) and Isospora belli (3.5%). Six cases of helminthiasis were also identified. Candida albicans was the most common opportunistic mycosis agent (39.1%). Other fungal species detected included Geotrichum candidum, Candida pseudotropicalis and Trichosporon sp. but all of these were less common.

Persistent diarrhea caused by Isospora belli: therapeutic response to pyrimethamine and sulfadiazine

A 54-year-old human immunodeficiency virus (HIV)-positive homosexual man developed overwhelming watery diarrhea and marked weight loss over a 3-week period. Although Entamoeba histolytica and other nonpathogenic enteric protozoa were observed along with Isospora belli in this patient's stool specimens, they were promptly eradicated after metronidazole (flagyl) treatment. The presence of I. belli oocysts in various stages of development in the stool and clinical symptoms related to Isospora infection persisted for 10 more months despite treatment with combined chemotherapeutic agents. Clinical and parasitiological resolution was ultimately achieved through an 8-week course of pyrimethamine and sulfadiazine.

Chemotherapy of human and animal coccidioses: state and perspectives

The state and perspectives for chemotherapy of cyst-forming and non-cyst-forming coccidia in humans and animals are summarized. In toxoplasmosis the therapeutic care of transplacental infections, which have gone out of control because of immunodeficiency, is in the forefront of attempts at improvement. Predominant drugs in use are pyrimethamine combined with a sulfonamide or with clindamycin, or trimethoprim plus sulfamethoxazole. For reasons of tolerability in human immunodeficiency virus (HIV)-infected patients, after 3 months of therapy a maintenance treatment on 2 days a week has recently given very positive results. In cats, monensin and toltrazuril are effective against the intestinal developmental stages of Toxoplasma gondii, the later drug affecting to a reasonable extent the extraintestinal stages as well. Attempts to treat neosporosis and sarcocystosis remain in the initial stages. The same is true for cryptosporidiosis in humans and animals. A number of highly effective drugs are available for prophylaxis of poultry coccidiosis. Increasing problems with resistance have led to new treatment schemes such as shuttle and rotation programs. In addition to a new polyether, semduramycin, a benzeneacetonitrile derivative (diclazuril) has been developed in recent years. After three decades a new drug (toltrazuril), a symmetrical triazinone derivative, has brought improvements for therapy and/or metaphylaxis in coccidiosis of poultry and mammals. The increasing possibilities for vaccination may result in new aspects for the use of chemotherapeutics, i.e., new combinations and/or shuttle or rotation programs.

Epidemiology of isosporiasis among persons with acquired immunodeficiency syndrome in Los Angeles County

To determine factors associated with isosporiasis in persons with acquired immunodeficiency syndrome (AIDS) in Los Angeles County, data from the AIDS surveillance registry were analyzed for the eight-year period 1985-1992. Isosporiasis was reported in 127 (1.0%) of 16,351 persons with AIDS during the study period. Prevalence of infection was highest among foreign-born patients (3.2%), especially those from El Salvador (7.4%) and Mexico (5.4%), and in all persons of Hispanic ethnicity (2.9%). Persons with a history of Pneumocystis carinii pneumonia (PCP) were less likely than PCP-negative patients to have isosporiasis (0.2% and 1.4%, respectively, P < 0.01). A decrease in the prevalence of isosporiasis in patients negative for PCP was observed beginning in 1989 (P = 0.02). Prevalence decreased with age (P < 0.01, by chi-square test for trend). After controlling for multiple factors by logistic regression, isosporiasis was more likely to occur in foreign-born patients than in those born in the United States (adjusted odds ratio [OR] = 5.8, 95% confidence interval [CI] 3.4, 9.9, P < 0.001) and in Hispanics than in whites (non-Hispanics) (adjusted OR = 3.5, 95% CI 1.7, 7.2, P < 0.001). A prior history of PCP continued to be negatively associated with isosporiasis (adjusted OR = 0.2, 95% CI 0.1, 0.3, P < 0.001). Age and time remained independently associated with infection. These data suggest that isosporiasis among persons with AIDS in Los Angeles County may be related to travel exposure and/or recent immigration and that the use of trimethoprim-sulfamethoxazole (TMP-SMX) for PCP may effectively prevent primary infection or expression of latent isosporiasis. Physicians should have an increased index of suspicion for Isospora in AIDS patients with diarrhea who have immigrated from or traveled to Latin America, among Hispanics born in the United States, in young adults, and in those not receiving PCP prophylaxis. Food and water precautions should be advised and TMP-SMX prophylaxis considered for the prevention of Isospora infection for patients with human immunodeficiency virus infection who travel to Latin America and other developing countries.

Contamination of soil with parasite eggs in Surabaya, Indonesia

Soil was examined for contamination by parasite eggs in Surabaya Indonesia. Surveys were carried out on three occassion; July, 1993 (dry season), March, 1994 (rainy season), and August, 1994 (dry season). Throughout the study, five species of nematode eggs (Ascaris lumbricoides, Toxocara cati, Trichuris trichiura, Physaloptera sp, Capillaria sp), two species of cestode eggs (Hymenolepis diminuta, Spirometra erinacei), and one species of protozoa oocyst (Isospora felis) were detected. The contamination rate and number of species found from the soil were significantly different in the dry and rainy seasons. In the dry season, the prevalence was 8-20%, with two to four species detected. During the rainy season, this rate was 83% with eight species, suggesting parasite infection to possibly occur mainly in this season. The reason for this seasonal difference may be that, in spite of constant temperature around 27 to 29 degrees C throughout the year, rainfall in the dry season in only a few percent of that of the rainy season. We concluded that parasite eggs die during the dry season owing to dryness of the soil. Contamination of soil with parasite eggs and the number of species found were greater in alley-ways and at communal water supply sites around residential areas than in open-air parks or sandy beaches. The method used in the present study proved extremely effective for ascertaining the actual dynamics of parasite infection in a certain region.

Intestinal opportunistic parasites among different groups of immunocompromised hosts

The present study was designed to find out the prevalence of different intestinal opportunistic parasites in different groups of immunocompromised hosts; patients suffering from malignancy with or without immuno-suppressive drugs, or with chronic renal failure, or diabetes mellitus, or subjects under cortisone therapy. Examination of stool samples collected from 427 immunocompromised hosts revealed the detection of intestinal opportunistic parasites in 98 samples, with a prevalence of 23%. Infection with opportunistic parasites was higher in males than in females (32.6% versus 12.9%). There was statistically significant association of infection with G. lamblia and Cryptosoporidium in the mixed infection detected. The highest group affected with the opportunistic parasites was the group of patients under corticosteroid therapy (31.7%), followed by patients suffering from renal failure (28.8%) and malignancy (25.7%), while the least group affected were the diabetic patients (8%). The highest prevalence rate was 10.3% for G. lamblia, being followed by E. histolytica (7%), C. parvum (6.3%), Microsporidia (2.3%) and the least one was for Strongyloides (0.7%). No cases of Isospora belli infection was detected. Relation between presence of opportunistic parasites and risk factors was discussed and evaluated.

The prevalence of Isospora suis and Strongyloides ransomi in suckling piglets in The Netherlands

Faecal samples from suckling piglets from 113 litters on 25 farms in the Netherlands were examined to study the prevalence of gastrointestinal parasites, in particular Strongyloides ransomi and Isospora suis. S. ransomi was not found but I. suis was demonstrated in 17 of the 25 farms and in 41 out of 77 litters of these farms (53%). No other parasites were found. On the basis of these results, a longitudinal study on the incidence and significance of I. suis was performed on 10 farms (5 litters/farm). I. suis was found on 9 out of 10 farms and in 56% of the litters. Farms differed in infection levels, measured as the numbers of patent litters, and in the onset of patency. Other parasites were only found in faecal samples from the sows and from farrowing pens. These were, in order of prevalence, Balantidium coli, Ascaris suum, Eimeria spinosa, E. debliecki and E. suis.

Parasitic gastroenteritis

Parasitic causes of diarrhea are common in pediatric patients and have important public health implications. Therefore, diagnosis should be pursued vigorously in the appropriate clinical setting. Giardia and Cryptosporidium infections are the most common causes of disease in the United States, and stool examination for ova and parasites is the best way to make the diagnosis. This should be performed three times, on alternate days, in order to rule out parasitic disease with confidence. In treatment of Giardia, it is important to interrupt transmission, particularly in the day-care setting. Because of the potential for major outbreaks, patients with cryptosporidiosis should be kept out of day care until their symptoms resolve. Although amebiasis is not a common problem in the United States, all patients with bloody diarrhea who have traveled to, or are from, endemic areas should be tested for amebiasis by serology and stool examination. If patients with suspected inflammatory bowel disease are being considered for therapy with corticosteroids, mucosal scrapings of colonic lesions should be examined for amoebae, because corticosteroid therapy can lead to more invasive amoebic disease. Acquired immunodeficiency syndrome patients with diarrhea can be infected with a number of pathogens and a specific diagnosis should be pursued aggressively. These patients are often infected with one or more of the parasites described in this article. The approach to diarrhea in these children is described in a separate article of this issue (Deveikis A. 'Gastrointestinal Disease in Immunocompromised Children," pages 562-569).